The document discusses how to write tests in Django. It explains the basic structure of a test with three parts: prepare, run, and assert. It provides examples of testing URLs, models, views, templates, and more. Various testing tools for Django are also covered, including RequestFactory, TestCase.client, and mocking with unittest.mock. The document concludes by addressing how to make the Python built-in module __future__ iterable in order to test that passengers are sent back to the future.

1. How to write
test
Shunsuke Hida
飛田 俊介
in Django

2. Geekhouse

3. Shinjuku
Akihabara

4. Castalia

5. Goocus

6. Django 1.7
Python 3. 4. 2

7. Structure of
test

8. 1. Prepare
def test_de_lorean_get_people_back_to_the_future(self):
de_lorean = DeLorean()
brown, marty, jeniffer = Brown(), Marty(), Jeniffer()
de_lorean.passengers = [brown, marty, jeniffer]
de_lorean.run()
self.assertIn(brown, __future__)
self.assertIn(marty, __future__)
self.assertIn(jeniffer, __future__)

9. 2. Run
def test_de_lorean_get_people_back_to_the_future(self):
de_lorean = DeLorean()
brown, marty, jeniffer = Brown(), Marty(), Jeniffer()
de_lorean.passengers = [brown, marty, jeniffer]
de_lorean.run()
self.assertIn(brown, __future__)
self.assertIn(marty, __future__)
self.assertIn(jeniffer, __future__)

10. 3. Assert
def test_de_lorean_get_people_back_to_the_future(self):
de_lorean = DeLorean()
brown, marty, jeniffer = Brown(), Marty(), Jeniffer()
de_lorean.passengers = [brown, marty, jeniffer]
de_lorean.run()
self.assertIn(brown, __future__)
self.assertIn(marty, __future__)
self.assertIn(jeniffer, __future__)

11. What can you test?

12. Request
Response
What can you test?
urls.py
Model
View
Template
View HTML
etc…
url
Context
get, save
render
dispatch
Data

13. Request
Response
What can you test?
urls.py
Model
View
Template
View HTML
etc…
url
Context
get, save
render
dispatch
Data

14. Request
Response
What can you test?
urls.py
Model
View
Template
View HTML
etc…
url
Context
get, save
render
dispatch
Data

15. RequestFactory
class HelloWorldTestCase(TestCase):
def test_hello_world_template(self):
factory = RequestFactory()
request = factory.get('/')
response = render(
request,
template_name='sample_app/hello_world.html',
dictionary=dict(message='hello')
)
self.assertContains(response, 'hello')

16. Request
Response
What can you test?
urls.py
Model
View
Template
View HTML
etc…
url
Context
get, save
render
dispatch
Data

17. TestCase.client
class HelloWorldTestCase(TestCase):
def test_hello_world_view(self):
response = self.client.get('/sample_app/hello_world/')
self.assertTemplateUsed(response, 'sample_app/hello_world.html')
self.assertEqual(response.context['message'], 'Hello World')

18. Mock
unittest.mock (new in Python 3.3)

19. Request
Response
What can you test?
urls.py
Model
View
Template
View HTML
etc…
url
Context
get, save
render
dispatch
Data

20. Mock - return_value
class Chapter(models.Model):
name = models.CharField(max_length=255)
def get_name(self):
return 'chapter ' + self.name
ChapterView
get_name

21. Mock - return_value
@mock.patch('sample_app.models.Chapter.get_name')
def test_get_name(self, mock_get_name):
mock_get_name.return_value = ‘abc'
chapter = ChapterFactory()
# chapter.get_name() == ‘abc’

22. Mock - assert_called_with
@mock.patch('sample_app.models.Chapter.get_name', autospec=True)
def test_chapter_get_name_is_called(self, mock_get_name):
chapter = ChapterFactory()
# call chapter.get_name() somewhere
mock_get_name.assert_called_with(
chapter,
prefix='chapter '
)

23. Mock
Mocked
Chapter
View
get_name
assert_called_with
return_value

24. See Also
Obey the Testing Goat!
(Test Driven Development with Python)
http://www.obeythetestinggoat.com/
Test of Django itself
https://github.com/django/django/tree/
master/tests

25. Can they go back to the
future?
def test_de_lorean_get_people_back_to_the_future(self):
de_lorean = DeLorean()
brown, marty, jeniffer = Brown(), Marty(), Jeniffer()
de_lorean.passengers = [brown, marty, jeniffer]
de_lorean.run()
self.assertIn(brown, __future__)
self.assertIn(marty, __future__)
self.assertIn(jeniffer, __future__)
TypeError: argument of type 'module' is not iterable
__future__

26. import types
import __future__
class IterableModule(types.ModuleType):
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
self.people = []
def __iter__(self):
return iter(self.people)
class DeLorean(object):
def __init__(self):
self.passengers = []
def run(self):
future = globals()['__future__'] = IterableModule('__future__')
for passenger in self.passengers:
future.people.append(passenger)

27. import
import
class
class
.
----------------------------------------------------------------------
Ran 1 test in 0.000s
OK

28. Thank you!